Insert element for a turbine of an exhaust gas turbocherger, exhaust gas turbocharger and turbine for an exhaust gas turbocharger

ABSTRACT

In a turbine of an exhaust gas turbocharger an insert element which is provided for insertion into a turbine housing has a spiral port which extends in the circumferential direction of the insert element over at least part of the circumference thereof and by which the exhaust gas flow through the turbine is controlled. The insert element is open in the axial direction on at least at one end face thereof which end face is biased in sealing contact with the turbine housing. The insert element has a central axial opening with a spiral port for accommodating a turbine wheel.

This is a Continuation-In-Part application of pending international patent application PCT/EP201100530 filed Oct. 21, 2011 and claiming the priority of German patent application 10 2010 051 359.8 filed Nov. 13, 2010.

BACKGROUND OF THE INVENTION

The invention relates to an insert element for a turbine of an exhaust gas turbo-charger, an exhaust gas turbocharger for an internal combustion engine, and a turbine for an exhaust gas turbocharger.

DE 25 39 711 discloses a spiral housing for continuous-flow machines, in particular in an exhaust gas turbocharger having a cross section that is adjustable at least in part, wherein at least one tongue that is slidingly guided on the radially inner wall of the spiral housing and can be displaced in connection with this wall in the circumferential direction is provided.

DE 10 2008 039 085 A1 discloses as known an, internal combustion engine for a vehicle comprising an exhaust gas turbocharger. The exhaust gas turbocharger comprises a compressor in an induction system of the internal combustion engine and a turbine in an exhaust gas system of the internal combustion engine, wherein the turbine has a turbine housing comprising a spiral port coupled to an exhaust gas line of the exhaust gas system, and a turbine wheel. The turbine wheel is arranged within an accommodating space of the turbine wheel and, for the purposes of driving a compressor wheel of the compressor connected via a shaft in a rotationally fixed manner to the turbine wheel, may be acted upon by exhaust gas from the internal combustion engine guided through the spiral port. The turbine comprises an actuating device by means of which a spiral entry cross section of the spiral port and a nozzle cross section of the spiral port can be jointly adjusted to the accommodating space.

There is further potential to reduce the production costs of known exhaust gas turbochargers.

It is the principal object of the present invention to provide an insert element for a turbine of an exhaust gas turbocharger, an exhaust gas turbocharger for an internal combustion engine and a turbine for an exhaust gas turbocharger, which result in lower exhaust gas turbocharger production costs.

SUMMARY OF THE INVENTION

In a turbine of an exhaust gas turbocharger an insert element which is provided for insertion into a turbine housing has a spiral port which extends in the circumferential direction of the insert element over at least part of the circumference thereof and by which the exhaust gas flow through the turbine is controlled. The insert element is open in the axial direction on at least at one end face thereof which end face is biased in sealing contact with the turbine housing. The insert element has a central axial opening with a spiral port for accommodating a turbine wheel.

The insert element can be produced particularly quickly and inexpensively owing in particular to the open design of the spiral port. The insert element is, for example, produced as a turned part and/or as a milled part, i.e. by turning and/or milling, or by some other production process, in particular involving cutting. It is also possible for the insert element o be designed as an investment cast part using an investment casting process. The insert element can also be produced through a combination of production processes, in particular the production processes described. Expensive and cost-intensive casting processes, for example with lost core, are unnecessary, in particular owing to the open design of spiral port. This keeps down the costs of producing the insert element and therefore the turbine, which advantageously allows particularly low production costs for the exhaust gas turbocharger.

In one advantageous embodiment of the invention, the spiral port is designed to be circumferentially completely open at least at one end face in the circumferential direction of the insert element and therefore of the turbine. This allows the particularly quick and inexpensive production of the insert element, resulting in low exhaust gas turbocharger production costs. When it comes to the series construction of motor vehicles, exhaust gas turbochargers are components which have to be produced in particularly large numbers, The low production costs made possible by the insert element according to the invention therefore have a particularly advantageous effect in reducing the costs of motor vehicles owing to economies of scale.

The insert element according to the invention also provides for a particularly favorable guidance of the exhaust gas flowing through the turbine, which, for example, is in the form of a radial turbine, to a turbine wheel of the turbine, which is arranged, in the assembled state of the exhaust gas turbocharger, within the insert element. The spiral port has an outlet opening which the turbine wheel is to be acted upon with exhaust gas flowing through the spiral port. In other words, the spiral port allows the exhaust gas to be guided such that the latter can flow towards the turbine wheel at least essentially in the radial direction of the insert element for driving the turbine wheel.

In one advantageous embodiment of the invention, the insert element has at least one further spiral port which extends in the circumferential direction of the insert element over at least part of the circumference thereof and through which the exhaust gas flowing through the turbine can flow, wherein the further spiral port is designed to be open at in part in the axial direction on at least one end face of the insert element. This means that the insert element can be produced particularly quickly and inexpensively even if a number of spiral ports, i.e. at least two, three or more, are provided. The insert element with the number of spiral ports also allows particularly favorable flow towards the turbine wheel so that the turbine can be operated particularly efficiently. This efficient operation of the turbine owing to the favorable flow conditions as far as the turbine wheel is concerned also has a very beneficial effect in terms of increasing the efficiency of the exhaust gas turbocharger as a whole, keeping down the fuel consumption and the CO₂ emissions of an internal combustion engine assigned to the exhaust gas turbocharger which is to be charged using the exhaust gas turbocharger.

It is noted at this point that the insert element can also be used in an exhaust gas turbocharger of an internal combustion engine or for other fluid energy machines, in particular for charging units. The insert element according to the invention can for example be used in a charging unit for a turbo engine or for a fuel cell, In this case, exhaust gas from the fuel cell flows through the turbine, wherein the exhaust gas from the fuel cell can be guided to the turbine wheel in a particularly favorable way by means of the insert element according to the invention.

If the insert element according to the invention has a number of spiral ports, then they are arranged, for example, in the circumferential direction of the insert element behind one another and/or in the axial direction at the same height It is also possible for the spiral ports to be arranged in the axial direction of the insert element next to one another and/or in the circumferential direction at the same height. The corresponding arrangement of the spiral ports has to be matched here to the corresponding conditions of use of the turbine and chosen accordingly.

The second aspect of he invention relates to an exhaust gas turbocharger for an internal combustion engine, which comprises a turbine and at least one insert element, in particular an insert element according to the invention, accommodated at least in part in a turbine housing of the turbine. The insert element has at least one spiral port which extends in the circumferential direction of the insert element over at least part of the circumference thereof and through which the exhaust gas flowing through the turbine can flow, which spiral port is designed to be open at least in part in the axial direction of the exhaust gas turbocharger on at least one end face of the insert element. Advantageous embodiments of the first aspect of the invention are to be regarded as advantageous embodiments of the second aspect of the invention and vice versa. As already described in relation to the first aspect of the invention, the insert element can be produced particularly inexpensively owing in particular to the open design of the spiral port, which has a positive effect in terms of reducing the costs of producing the turbine and therefore the exhaust gas turbocharger as a whole.

In one advantageous embodiment of the second aspect of the invention, the spiral port is designed to be open at least in part in the axial direction of the exhaust gas turbocharger on one end face of the insert element pointing in the direction of an outlet of the turbine and/or the exhaust gas turbocharger comprises a bearing housing for bearing a rotor of the exhaust gas turbocharger, wherein the spiral port is designed to be open at least in part in the axial direction of the exhaust gas turbocharger on one end face of the insert element pointing in the direction of the bearing housing. Through the at least one spiral port, the insert element provides here for a particularly favorable guidance of the exhaust gas to a turbine wheel of the turbine of the exhaust gas turbocharger so that the whole exhaust gas turbocharger operates particularly efficiently. At the same time, the insert element is particularly inexpensive to produce.

The insert element of the second aspect of the invention is, for example, also designed as a turned part and/or as a milled part, i.e. by turning and/or milling, or by some other production process, in particular involving cutting, and/or as a component that can be produced through an investment casting process. The insert element of the second aspect of the invention can also be produced through a combination of the production processes described or through a combination of other production processes.

It is also possible for the insert element of both the first and the second aspect of the invention to be in the form of a sheet metal part comprising a number of pieces of sheet metal welded together and/or connected or joined in some other way.

In order to be able to cover the at least one spiral port or the numerous spiral ports and therefore be able to guide the exhaust gas to the turbine wheel in a favorable way, the insert element of the second aspect of the invention is located, for example, abutting a further component of the exhaust gas turbocharger. The insert element abuts the component, and the component covers the openly designed area of the spiral port, for example by means of a wall. The component is, for example, the turbine housing.

In order to avoid efficiency-reducing leakages, it is advantageous, by the application of force, to hold the insert element abutting, and therefore in contact with the component covering the open area of the spiral port. For this purpose, the insert element is for example supported indirectly on the bearing housing, as a result of which the insert element is held, by the application of force.

A spring element, in particular a disc spring, is advantageously provided, by means of which the insert element is supported on the bearing housing. The bearing housing can be supported here, at least in part, at least indirectly on the insert element or the component and/or in part on the turbine housing.

In a further embodiment of the invention, at least one lid element is provided, by means of which an area of the spiral port, in which the spiral port is designed to be open, is covered at least in part. Advantageously, the area of the spiral port that is designed to be open is completely covered by the lid element so that the exhaust gas can be guided to the turbine wheel in a particularly favorable way.

The lid element has the advantage that, in particular compared to the turbine housing and the insert element, it can have an uncomplicated and at least predominantly flat geometry in order to cover the spiral port in part. Owing to this uncomplicated geometry, in particular if the lid element is flat at least in part, the lid is distorted at least essentially uniformly during operation of the exhaust gas turbocharger under the stress of changing temperatures. As a result, efficiency-reducing leakages, where exhaust gas is able to flow out of the spiral port, are at least essentially avoided or the likelihood of such leakages is very small. It is advantageous if, by the application of force, the lid element is held at least indirectly on the insert element in order to cover the spiral port in a particularly tight manner. For this purpose, it is possible, for example, for the lid element to be supported, at least indirectly, on the one hand, on the insert element and, on the other hand, on the bearing housing. It is also possible to use at least one spring element by which the lid element is forced against the insert element and held particularly firmly on it.

A further embodiment keeping down the cost of producing the exhaust gas turbocharger of the second aspect of the invention is for the insert element to be separate from the turbine housing and to be inserted into the turbine housing in part during assembly of the exhaust gas turbocharger. This means that the turbocharger can be assembled quickly and inexpensively.

The third aspect of the invention relates to a turbine for an exhaust gas turbocharger, with a turbine housing having an accommodating space for accommodating a turbine wheel, which comprises at least one spiral port through which the exhaust gas flowing through the turbine can flow and which extends in the circumferential direction of the accommodating space over at least part of the circumference thereof, the spiral port having at least one inlet opening allowing exhaust gas to flow into the spiral port, wherein exhaust gas can be guided to the accommodating space via the spiral port.

According to the invention, at least one port part is provided, by means of which the at least one spiral port is divided into at least two spiral ports downstream of the inlet opening. Advantageous embodiments of the first two aspects are to be regarded as advantageous embodiments of the second aspect of the invention and vice versa. In other words, through the port part, at least two spiral part ports are formed which, during operation of the turbine, are supplied with exhaust gas via the spiral port common to the spiral part ports.

An exhaust gas stream flowing through the spiral port is divided by the spiral part ports into respective part streams so that the exhaust gas can flow particularly favorably towards the turbine wheel accommodated in the accommodating space and the latter can therefore be driven. This allows a particularly efficient and favorable operation of the turbine. This also keeps down production complexity and therefore the costs of producing the turbine and therefore the exhaust gas turbocharger as a whole.

The port part of the third aspect of the invention is, for example, designed as an insert element and therefore as an element that is separate from the turbine housing which is accommodated in the turbine housing. This allows particularly inexpensive manufacture of the port part and of the turbine as a whole. The port part is for example produced by machining and/or milling, or by some other manufacturing process, in particular involving cutting. It is also possible for the port part designed as an insert element to be produced using an investment casting process. As in the first two aspects of the invention, it is likewise possible for the port part designed as an insert element to be produced by a combination of production processes and/or the production processes described.

In a further embodiment of the third aspect of the invention, the port part is designed to be integral with the turbine housing. The port part is, for example, milled into the turbine housing here. To produce the turbine housing and the port part designed to be integral with the latter, provision can be made for a rough outline of the port part to be cast, for example through a sand casting process, and an exact final outline of the port part, in particular of the spiral part ports, to be shaped by means of mechanical processing, for example milling.

Like the insert elements of the first two aspects of the invention, the port part of the third aspect of the invention can also have a number of spiral ports, i.e. at least two, three or more, which, for example, are arranged in the circumferential direction of the port part over the circumference thereof behind one another or in the axial direction at the same height or in the circumferential direction at the same height and/or in the axial direction next to one another. The corresponding arrangement also has to be matched here to the conditions of use of the turbine of the third aspect of the invention and chosen accordingly.

In a further embodiment of the third aspect of the invention, at least one of the spiral part ports of the port part designed in particular as an insert element is designed to be open at least in part in the axial direction of the turbine on at least one end face of the port part. This means that the port part can be produced particularly inexpensively, in particular if the spiral part port is designed to be circumferentially completely open in the circumferential direction of the port part.

The area in which the spiral part port of the port part of the third aspect of the invention is designed to be open can, for example, be designed to be open in the direction of an outlet of the turbine or in the direction of a bearing housing of the exhaust gas turbocharger with the turbine of the third aspect of the invention.

It is likewise possible for the spiral part ports of the port part of the third aspect of the invention, in particular if the latter is designed as an insert element, to be circumferentially completely enclosed in the axial direction of the turbine on both end faces in the circumferential direction. This allows, on the one hand, the particularly favorable guiding of the exhaust gas to the accommodating space and, on the other, particularly quick and inexpensive assembly and therefore production of the turbine of the exhaust gas turbocharger since the port part designed in particular as an insert element can be incorporated easily and quickly at least in part into the turbine housing and arranged there.

The fourth aspect of the invention relates to an exhaust gas turbocharger having a turbine according to the third aspect of the invention, wherein in particular in the axial direction of the exhaust gas turbocharger or of the turbine, between a housing part, in particular a bearing housing, of the exhaust gas turbocharger and the port part, an interspace delimited from the port part at least in part, in particular in the axial direction at least in part, is formed which is connected in flow terms to the at least one spiral port. Advantageous embodiments of the first three aspects of the invention are to be regarded as advantageous embodiments of the fourth aspect of the invention and vice versa. This flow connection means that at least essentially equal pressure prevails in the spiral port and in the interspace. This pressure can then act, in particular at least essentially in the axial direction, on a wall of the port part, wherein the wall, on the one hand, delimits the interspace and, on the other, delimits at least one of the spiral part ports. On the spiral part port side, which is delimited by this wall, a lower pressure acts on the wall than on the interspace side since, in the individual spiral part ports, a pressure, in particular a static pressure, prevails which is lower than the pressure, in particular the static pressure, in the interspace or in the at least one spiral port.

As a result of this described pressure difference, force is applied to the port part acting in a corresponding, in particular at least essentially axial direction. This application of force can be used to force the port part designed in particular as an insert element against a further component of the exhaust gas turbocharger and to hold the port part, through the application of force, at least indirectly on the component.

If at least one of the spiral part ports on the at least one end face is designed to be open at least in part, then this application of force can be used to hold the port part on the corresponding component, wherein the component can then tightly cover that area of the spiral port designed to be open. As a result, efficiency-reducing leakages, where exhaust gas is able to flow out of the open spiral part port, are at least essentially avoided.

It is also possible, in the second and third aspects of the invention, for a corresponding interspace according to the fourth aspect of the invention to be provided between the insert element and a housing part of the turbine or of the exhaust gas turbocharger, wherein the interspace is connected in flow terms to a further spiral port, in particular a feed port, so that a higher pressure prevails in the interspace than in the at least one spiral port formed by the insert element. Then, the insert element can, in a way described in relation to the fourth aspect of the invention, be held similarly through the application of force on a component, for example the lid element, or a housing part, for example the turbine housing, in order to cover at least essentially tightly that area of the spiral port formed by the insert element that is designed to be open.

The fifth aspect of the invention relates to a turbine for an exhaust gas turbocharger, with a turbine housing which has at least one spiral port and an accommodating space in which a turbine wheel is to be accommodated such that it can rotate. The turbine wheel can be acted upon with exhaust gas via the spiral port, wherein the turbine comprises an actuating device by means of which a spiral inlet cross section and/or a nozzle cross section of the at least one spiral port can be adjusted to the accommodating space.

According to the invention, in the fifth aspect of the invention, provision is made for the actuating device to have at least two intermeshing tooth systems for the purposes of adjusting the spiral inlet cross section and/or the nozzle cross section. Advantageous embodiments of the first four aspects of the invention are to be regarded as advantageous embodiments of the fifth aspect of the invention and vice versa. The adjustment of the spiral inlet cross section and/or of the nozzle cross section via the tooth systems allows a particularly large adjustment range, in particular adjustment angle range, in which the spiral inlet cross section and/or the nozzle cross section can be variably adjusted. This allows a particularly high through-put spread of the variable turbine of the fifth aspect of the invention, as a result of which the turbine can be adapted particularly efficiently to a number of operating points of an internal combustion engine assigned to the exhaust gas turbocharger. This results in a particularly efficient operation of the turbine in the at least virtually entire characteristic map of the internal combustion engine, so that the latter can be operated particularly efficiently and with a low fuel requirement and low CO₂ emissions.

Owing in particular to its adjustability via the tooth systems which are advantageously arranged in the turbine housing, the turbine also has only a small space requirement, which helps to solve or to avoid packaging problems, in particular in an area such as an engine bay where space is critical.

In order to adjust the spiral cross section and/or the nozzle cross section, the actuating device comprises at least one assigned blocking element in the spiral port, for example a tongue which can be moved in the circumferential direction of the accommodating space or of the turbine wheel.

A further advantage of the tooth system is that a harmonic transmission between an adjustment member for moving the blocking unit and the blocking unit itself can be achieved over the adjustment range.

The adjustment unit is arranged, for example, on an adjustment ring which is arranged in the turbine housing such that it can be rotated about a rotational axis via the tooth systems and the adjustment member. If the ring is turned, then the blocking element also moves so that the spiral inlet cross section and/or the nozzle cross section are variably adjusted, i.e. can be made larger or smaller.

In one advantageous embodiment of the invention, provision is made for one of the tooth systems to be provided on the adjustment ring of the actuating device and for the other tooth system to be connected in a rotationally fixed manner to an adjustment shaft of the actuating device that can be rotated about a rotational axis. The adjustment ring is connected to the adjustment member here via the adjustment shaft. The adjustment member is for example, an electric motor with an output shaft which can be rotated about a rotational axis in order to move the blocking unit. The adjustment shaft is connected here to the output shaft or formed by the output shaft so that turning the output shaft of the electric motor causes the adjustment shaft to turn and therefore the blocking unit to move.

Further advantages, features and details of the invention will become more readily apparent from the following description of preferred exemplary embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 Is an axial cross-sectional view of an exhaust gas turbocharger for an internal combustion engine having a turbine with an turbine housing in which a multi-segment insert is inserted;

FIG. 2 Is a perspective view of the multi-segment insert of the turbine according to FIG. 1;

FIG. 3 Is a schematic cross-sectional view of the turbine of the exhaust gas turbocharger according to FIG. 1;

FIG. 4 Is a schematic axial cross-sectional view of a further embodiment of the exhaust gas turbocharger according to FIG. 1;

FIG. 5 Is a schematic perspective view of a multi-segment turbine insert of the exhaust gas turbocharger according to FIG. 4,

FIG. 6 Is a schematic cross-sectional view of the turbine of the exhaust gas turbocharger according to FIG. 4;

FIG. 7 Shows a section of a further embodiment of the exhaust gas turbocharger according to FIGS. 1 and 4;

FIG. 8 Shows a section of a still further embodiment of the exhaust gas turbocharger according to FIG. 7;

FIG. 9 Shows a section of a further embodiment of the exhaust gas turbocharger according to FIGS. 7 and 8;

FIG. 10 Shows another sectional view of a further embodiment of the exhaust gas turbocharger according to FIGS. 7 to 9;

FIG. 11 Shows a section of a further embodiment of the exhaust gas turbocharger according to FIGS. 7 to 10;

FIG. 12 Shows a section of a further embodiment of the exhaust gas turbocharger according to the above figures; and

FIG. 13 Shows schematically a front view in a transverse sectional of the exhaust gas turbocharger according to FIG. 12.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the figures, the same reference numerals refer to at least functionally identical elements, components and/or the like.

FIG. 1 shows part of an exhaust gas turbocharger 10 having a turbine 12 which comprises a turbine housing 14 and a bearing housing 16. The turbine housing 14 forms an accommodating space 18 in which a turbine wheel 20 of a rotor 22 of the exhaust gas turbocharger 10 is accommodated such that it can rotate. The rotor 22 also comprises a shaft 24 to which the turbine wheel 20 is connected in a rotationally fixed manner.

The exhaust gas turbocharger 10 also comprises a compressor not shown in FIG. 1 with a compressor housing by which an accommodating space is formed in which a compressor wheel of the rotor 22 is accommodated. The compressor wheel is also connected to the shaft 24 in a rotationally fixed manner so that the compressor wheel can be driven via the shaft 24 and the turbine wheel 20. The rotor 22 is supported in the bearing housing 16 and can rotate about a rotational axis 26.

By the turbine housing 14, a spiral port 28 is formed in part which serves as a feed port. In the spiral port 28, exhaust gas can flow into an internal combustion engine assigned to the exhaust gas turbocharger 10 in the direction of an arrow 32 via an inlet opening 30 of the spiral port 28. The exhaust gas then flows through the spiral port 28 in the direction of an arrow 34.

A multi-segment insert 36 shown in perspective and schematic view in FIG. 2 is arranged in the turbine housing 14, through which the spiral port 28 is formed by means of a wall 68 in part. The multi-segment insert 36 of the exhaust gas turbocharger 10 according to FIGS. 1 to 3 is designed as an insert element that is separate from the turbine housing 14 and has four spiral ports 38, 40, 42 and 44 which extend in the circumferential direction of the multi-segment insert 36 in the direction of an arrow 46 in part over the circumference of the multi-segment insert 36. The spiral ports 38, 40, 42 and 44 are arranged in the circumferential direction behind one another and in the axial direction of the multi-segment insert 36 and therefore of the exhaust gas turbocharger in the direction of an arrow 49 at the same height.

As can be seen in FIG. 3 in particular, the spiral port 28 extending in the circumferential direction of the accommodating space 18 and therefore of the turbine wheel 20 in the direction of an arrow 48 at least in part over the circumference of the accommodating space 18 and functioning as a feed port is divided into the spiral ports 38, 40, 42 and 44 by means of the multi-segment insert 36 downstream of the inlet opening 30. The spiral ports 38, 40, 42 and 44 are connected in flow terms to the spiral port 28 and are therefore supplied with exhaust gas from the spiral port 28 common to the spiral ports 38, 40, 42 and 44. As a result, the exhaust gas flows to the turbine wheel 20 at least essentially in the radial direction thereof in a particularly favorable way and acts thereon so that the exhaust gas turbocharger 10 operates particularly efficiently and favorably.

For this purpose, the spiral ports 38, 40, 42 and 44 have respective outlet openings 50, 51, 52 and 53 via which the spiral ports 38, 40, 42 and 44 open into the accommodating space 18 and via which the exhaust gas can flow to the turbine wheel 20 at least essentially in the radial direction of the turbine wheel 20 and of the multi-segment insert 36 in the direction of an arrow 54. The turbine 12 is therefore a radial turbine.

The exhaust gas turbocharger 10 also comprises an actuating device 56 with respective tongues 58, 60, 62 and 64 assigned to the spiral ports 38, 40, 42 and 44 or to the corresponding outlet openings 50, 51, 52 and 53. The tongues 58, 60,'62 and 64 are connected to an adjustment ring 66 which can be rotated about the rotational axis 26. Turning the adjustment ring 66, which also is referred to as a tongue diverter, produces an adjustment, in particular a displacement, of the tongues 58, 60, 62 and 64 in the circumferential direction as shown by the arrow 48. By this movement or displacement of the tongues 58, 60, 62 and 64, a spiral inlet cross section A_(S) of the spiral ports 38, 40, 42 and 44 (wherein the overview in FIG. 3 shows a representation of all spiral inlet cross sections A_(S) of the spiral inlet cross sections 38, 40, 42 and 44 through the spiral inlet cross section A_(S) of the spiral port 38) and/or a nozzle cross section A_(R) of the spiral ports 38, 40, 42 and 44 (wherein the overview in FIG. 3 shows a representation of the nozzle cross sections A_(R) of the spiral ports 38, 40, 42 and 44 through merely the nozzle cross section A_(R) of the spiral port 38) can be variably adjusted.

In the multi-segment insert 36 of the exhaust gas turbocharger 10 according to FIGS. 1 and 3, leakages between the spiral ports 38, 40, 42 and 44 and therefore a corresponding overflowing of exhaust gas from one of the spiral ports 38, 40, 42 and 44 into another of the spiral ports 38, 40, 42 and 44 as a result of the walls 70 and 72 delimiting and sealing the ends of the spiral ports 38, 40, 42 and 44 are avoided. As a result, the exhaust gas can be guided particularly favorably into the accommodating space 18 to the turbine wheel 29 and the exhaust gas turbocharger 10 displays a particularly high level of efficiency.

The multi-segment insert 36 can for example be formed as an integral component by an investment casting process. It is likewise possible for the multi-segment insert 36 to be designed as a sheet metal part comprising a number of pieces of sheet metal which, for example, form the walls 68, 70 and 72 and which are welded together.

By the four spiral ports 38, 40, 42 and 44, four segments are formed through which exhaust gas can flow and via which the exhaust gas can be guided towards the turbine wheel 20. Of course the multi-segment insert 36 can also have more or fewer spiral ports or segments.

As shown in FIG. 1 in particular, the multi-segment insert 36 is held in the turbine housing 14 in the axial direction as shown by the arrow 49 by means of the bearing housing 16. For this purpose, the multi-segment insert 36 is supported on the bearing housing 16 via respective contact surfaces 74, wherein the bearing housing 16 is connected, for example screwed, to the turbine housing 14. On the other hand, the segment insert 36 is supported on the turbine housing 14 via respective contact surfaces 76. As a result, the bearing housing 16 presses the multi-segment insert 36 in the axial direction as shown by the arrow 49 in the direction of a turbine outlet 78 in the direction of an arrow 80 against the turbine housing 14 and holds the multi-segment insert 36 in the axial direction therein. As a result, the multi-segment insert 36 is pressed into the turbine housing 14.

FIGS. 4 to 6 show an alternative embodiment of the exhaust gas turbocharger 10 according to the preceding FIGS. 1 to 3, which is designated as 10 ^(I). In the turbine housing 14 of the turbine 12 of the exhaust gas turbocharger 10 ^(I) there is provided a multi-segment insert 36 ^(I) which differs from the multi-segment insert 36 according to FIGS. 1 to 3 in that there is no wall 70. In other words, the spiral ports 38, 40, 42 and 44 of the multi-segment insert 36 ^(I) are designed to be circumferentially completely open in the axial direction thereof as shown by the arrow 49 on one end face 82 of the multi-segment insert 36 ^(I) in the circumferential direction thereof as shown by the arrow 48, In connection with FIG. 4, it can be seen that the open end face 82 points in the direction of the turbine outlet 78.

If the multi-segment insert 36 ^(I) allows particularly easy and inexpensive assembly and production of the exhaust gas turbocharger 10 and particularly efficient operation thereof, then the multi-segment insert 36 ^(I) itself is particularly inexpensive to produce owing to the open design of the spiral ports 38, 40, 42 and 44. The multi-segment insert 36 ^(I) is produced, for example, as a turned part and/or as a milled part, by an investment casting process or by a combination of production processes, in particular the production processes described.

In order to avoid efficiency-reducing leakages and therefore an overflowing of exhaust gas from one of the spiral ports 38, 40, 42 and 44 into another of the spiral ports 38, 40, 42 and 44, the multi-segment insert 36 ^(I) is held on its open end face 82 against the turbine housing 14 by means of the bearing housing 16 so that the turbine housing 14 completely and tightly covers the spiral ports 38, 40, 42 and 44 of the multi-segment insert 36 ^(I) with a corresponding area of a wall 86 of the turbine housing 14.

In order to hold the multi-segment insert 36 ^(I) in the turbine housing 14 in an axial direction as shown by the arrow 49 and force it against the turbine housing 14, the multi-segment insert 36 ^(I) is supported via a disc spring 75 on the bearing housing 16. The bearing housing 16 is supported here in part not only via the disc spring 75 on the multi-segment insert 36 ^(I), but also in part on the turbine housing 14. This means that the multi-segment insert 36 ^(I) is forced, under the application of spring force, by the disc spring 75 particularly firmly against the turbine housing 14 in the direction of the arrow 80 and held on the latter so that leakages are at least essentially avoided. As a result, the multi-segment insert 36 ^(I) is pressed into the turbine housing 14.

Otherwise, the description given in relation to the exhaust gas turbocharger 10 and the multi-segment insert 36 relating to FIGS. 1 to 3 applies analogously to the exhaust gas turbocharger 10 ^(I) and the multi-segment insert 36 ^(I) according to FIGS. 4 to 6.

FIG. 7 shows a further alternative embodiment of the exhaust gas turbochargers 10 and 10 ^(I) which is designated by 10 ^(II). In the turbine housing 14 of the turbine 12 of the exhaust gas turbocharger 10 ^(II), a multi-segment insert 36 ^(II) is accommodated which differs from the multi-segment insert 36 in that there is no end face wall 72. As a result, the spiral ports 38, 40, 42 and 44 are circumferentially completely open in the axial direction of the multi-segment insert 36 ^(II) or of the exhaust gas turbocharger 10 ^(II) in the direction of the arrow 49 on one end face 84 of the multi-segment insert 36 ^(II) in the circumferential direction thereof as shown by the arrow 49. Viewed in conjunction with FIG. 5, it can be seen that the end face 84 is arranged opposite the end face 82 in the axial direction. FIG. 7 shows that the open end face 84 of the multi-segment insert 36 ^(II) therefore points in the direction of the bearing housing 16.

In order to cover the spiral ports 38, 40, 42 and 44 of the multi-segment insert 36 ^(II) completely and at least essentially not also towards the end face 84, the exhaust gas turbocharger 10 ^(II) comprises a lid 86 which is likewise arranged in the turbine housing 14. The lid 86 has a flat wall 89 by means of which the spiral ports 38, 40, 42 and 44 are circumferentially completely covered in the circumferential direction. For this purpose, the lid 86 is supported on the multi-segment insert 36 ^(II) via respective contact surfaces 74 ^(II) and abuts against the multi-segment insert 36 ^(II). The multi-segment insert 36 ^(II) and the lid 86 are held in the axial direction by the bearing housing 16 which abuts via respective contact surfaces 74 ^(I) against the lid 86. In other words, the bearing housing 16, by means of the lid 86, abuts against the multi-segment insert 36 ^(II) which in turn abuts via the contact surfaces 76 against the turbine housing 14 and is supported thereon. Through this support chain, the lid 86 is forced by means of the bearing housing 16 on the multi-segment insert 36 ^(II) in the direction of the arrow 80, as a result of which leakages between the spiral ports 38, 40, 42 and 44 of the multi-segment insert 36 ^(II) are at least essentially avoided. As a result, the multi-segment insert 36 ^(II) is likewise pressed via the lid 86 and the lid 86 into the turbine housing 14. As in the case of the exhaust gas turbochargers 10 and 10 ^(I) according to the preceding FIGS. 1 to 6, in the case of the exhaust gas turbocharger 10 ^(II) according to FIG. 7 it is therefore also guaranteed, during operation, that the spiral ports 38, 40, 42 and 44 are at least essentially always tightly covered as a result of the multi-segment insert 36 ^(I) being forced, for example, against the turbine housing 14 or the lid 86 being forced against the multi-segment insert 36 ^(II) in order to avoid leakages and ensure favorable flow towards the turbine wheel 20.

FIG. 8 shows an alternative embodiment of the turbochargers 10, 10 ^(I) and 10 ^(II) according to the preceding figures, which is designated by reference numeral 10 ^(III). The exhaust gas turbocharger 10 ^(III) comprises a port part 37 which, in particular in respect of the spiral ports 38, 40, 42 and 44, is designed similarly to the multi-segment inserts 36, 36 ^(I) and 36 ^(II). The port part 37 differs from the multi-segment inserts 36, 36 ^(I) and 36 ^(II) in that the port part 37 is designed to be integral with the turbine housing 14 of the turbine 12 of the exhaust gas turbocharger 10 ^(III). The port part 37 is, for example, the multi-segment insert 36 ^(II) according to FIG. 7 which is designed to be integral with the turbine housing 14. As can be seen in FIG. 8, the spiral ports 38, 40, 42 and 44 of the port part 37 are designed to be circumferentially completely open in the axial direction as shown by the arrow 49 on the end face 84 of the port part 37 in the circumferential direction of the port part 37.

In order to cover tightly the spiral ports 38, 40, 42 and 44 of the port part 37, the lid 86 is provided which is forced by means of the bearing housing 16 in the axial direction as shown by the arrow 80 against the turbine housing 14, is therefore held thereon and is supported via contact surfaces 74 ^(II) on the latter. As a result, the lid 86 is pressed into the turbine housing 14.

In order to produce the port part 37 which is geometrically as sophisticated as the multi-segment inserts 36, 36 ^(I) and 36 ^(II), the port part 37 is, for example, milled into the turbine housing 14, wherein the spiral-shaped walls 68 which delimit the spiral ports 38, 40, 42 and 44 in a radial direction as shown by the arrow 54, are formed.

In the production of the turbine housing 14, for example by a sand casting process, a rough shape of the port part 37 can be formed first. The final outline of the port part 37 shown in FIG. 8 is then formed, for example, by means of mechanical processing.

FIG. 9 shows, by reference to a further embodiment of an exhaust gas turbocharger 10 ^(IV), a possible way of holding a multi-segment insert 36 ^(III) in the turbine housing 14 of the turbine 12 of the exhaust gas turbocharger 10 ^(IV).

The multi-segment insert 36 ^(III) is, for example, the multi-segment insert 36 of the exhaust gas turbocharger 10 according to FIGS. 1 to 3. The multi-segment insert 36 ^(III) also has the spiral ports 38, 40, 42 and 44 and the same function as the multi-segment insert 36.

As can be seen in FIG. 9, the multi-segment insert 36 ^(III) is held by means of the bearing housing 16 in the turbine housing 14, the bearing housing 16 being connected, for example screwed, to the turbine housing 14 so that the multi-segment insert 36 ^(III) is forced in the axial direction as shown by the arrow 49 onto the turbine housing 14 in the direction of the arrow 80. The arrows 88 show a leakage path from the spiral port 28 acting as a feed port to the surroundings, while the arrows 90 indicate a further leakage path from the spiral port 28 via an interspace 92 arranged in the axial direction between the multi-segment insert 36 ^(III) and the bearing housing 16 into the accommodating space 18. Owing to the particularly firm holding and pressing of the multi-segment insert 36 ^(III) in or into the turbine housing 14, these leakage paths are at least essentially avoided. In order to prevent such a leakage particularly effectively, sealing elements 94 can be arranged between corresponding contact surfaces of the bearing housing 16 with the multi-segment insert 36 ^(III) and/or with the turbine housing 14 and/or between contact surfaces of the multi-segment insert 36 ^(III) with the turbine housing 14 and between contact surfaces of the adjustment ring 66 with the bearing housing 16 and/or with the turbine housing 14 and/or with the multi-segment insert 36 ^(III).

FIG. 10 shows, by reference to a further embodiment of an exhaust gas turbocharger 10 ^(V), a further possible way of holding and pressing a multi-segment insert 36 ^(IV) of the exhaust gas turbocharger 10 ^(V) in its turbine housing 14 of the turbine 12. The multi-segment insert 36 ^(IV) is, for example, the multi-segment insert 36 ^(I) of the exhaust gas turbocharger 10 ^(I) according to FIGS. 4 to 6. The multi-segment insert 36 ^(IV) likewise has the spiral ports 38, 40, 42 and 44 and the same function as the multi-segment insert 36. As can be seen in FIG. 10, the bearing housing 16 is supported via respective contact surfaces 74 ^(II) on the turbine housing 14. In the axial direction as shown by the arrow 49, there is arranged between the multi-segment insert 36 ^(IV) and the bearing housing 16 the disc spring 75 which is therefore supported, one the one hand, on the multi-segment insert 36 ^(IV) and, on the other hand, on the bearing housing 16. Through the connection of the bearing housing 16 to the turbine housing 14 and as a result of the fact that the multi-segment insert 36 ^(IV) is supported via the contact surfaces 76 on the turbine housing 14, the disc spring 75 is prestressed so that the latter forces the multi-segment insert 36 ^(IV) in the axial direction as shown by the arrow 80 against the turbine housing 14 so that the spiral ports 38, 40, 42 and 44 are covered tightly by the turbine housing 14. In order to pre-stress the disc spring 75, a force acts on the bearing housing 16 in the direction of the arrow 80, which, for example, is effected by screwing the bearing housing 16 with the turbine housing 14 by means of a plurality of screws so that the bearing housing 16 is pressed via the contact surfaces 74 ^(II) against the turbine housing 14.

It is likewise possible for the disc spring 75 to be used, for example, in the exhaust gas turbochargers 10, 10 ^(II) and 10 ^(III) and to be arranged in the axial direction between the bearing housing 16 and the lid 86 and/or between the lid 86 and the corresponding multi-segment insert 36, 36 ^(II) or the port part 37 in order to avoid corresponding leakages.

Possible leakage paths are also indicated in FIG. 10 by the arrows 88 and 90, these leakages being at least essentially avoided through the particularly firm holding and pressing of the multi-segment insert 36 ^(IV) in or into the turbine housing.

The disc spring 75 has the advantage here that, even in the event of thermal expansion of the assembly of the turbine housing 14, the multi-segment insert 36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), the bearing housing 16 and, if applicable, the lid 86, it acts at least virtually always on the multi-segment insert 36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV) at least indirectly with the desired considerable force in order to cover tightly the spiral ports 38, 40, 42 and 44, for example through the turbine housing 14 and/or the lid 86.

FIG. 11 shows a further embodiment of an exhaust gas turbocharger 10 ^(VI) according to the exhaust gas turbochargers 10, 10 ^(II), 10 ^(III), 10 ^(IV) and 10 ^(V). The exhaust gas turbocharger 10 ^(VI) comprises a multi-segment insert 36 ^(V) which, for example, may be the multi-segment insert 36 ^(IV) or 36 ^(I). The multi-segment insert 36 ^(V) also has the spiral ports 38, 40, 42 and 44 and the same function as the multi-segment inserts 36 ^(IV) and 36 ^(I).

In the exhaust gas turbocharger 10 ^(VI), the interspace 92 is connected in flow terms to the spiral port 28 functioning as a feed port. For this purpose, for example, a number of through-openings 96, provided here in the form of bores, of which one through-opening 96 is shown in FIG. 11 as a representation. Owing to this flow connection, at least essentially the same pressure prevails in the interspace 92 as in the spiral port 28. This in particular static pressure in the interspace 92 is greater than a total static pressure in the individual spiral ports 38, 40, 42, 44 of the multi-segment insert 36 ^(V). As a result of this pressure difference, a force F acts via corresponding surfaces of the wall 72 on the multi-segment insert 36 ^(V) which is directed at least essentially in the axial direction as shown by the arrow 49 in direction of the turbine housing 14 as shown by the arrow 80.

As a result, the multi-segment insert 36 ^(V) is forced via the contact surfaces 76 against the turbine housing 14 of the turbine 12 and pressed into the latter so that the spiral ports 38, 40, 42 and 44 are at least essentially covered by the turbine housing 14. In a similar way, the force F can also be applied to the lid 86 in order to cover the spiral ports 38, 40, 42 and 44 at least essentially tightly. This is a particularly advantageous method of at least essentially preventing any leakages, for example the leakage paths indicated by the arrows 88 and 90.

FIGS. 12 and 13 show a further alternative embodiment of the exhaust gas turbocharger 10 according to the exhaust gas turbochargers 10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V) and 10 ^(VI). The exhaust gas turbocharger 10 ^(VII) also comprises a multi-segment insert 36 ^(VI) which is, for example, the multi-segment insert 36 or 36 ^(III).

The actuating device 56 comprises, in addition to the adjustment ring 66 and the tongues 58, 60, 62 and 64, an adjustment wheel 98, an adjustment shaft 100 and an adjustment lever 102. The adjustment ring 66 and the adjustment wheel 98 are each provided with a tooth system 104 and 106, these being arranged within the turbine housing 14 of the turbine 12 of the exhaust gas turbocharger 10 ^(VII) and meshing with one another. The adjustment wheel 98 is connected in a rotationally fixed manner to the adjustment shaft 100, which is held in the bearing housing 16 such that it can rotate about a rotational axis 108. The adjustment shaft 100 is also connected in a rotationally fixed manner to the adjustment lever 102 which is in part arranged in the turbine housing 14 and guided out of the bearing housing 16 via a through-opening. The adjustment lever interacts with an actuator of the exhaust gas turbocharger 10 ^(VII), this being, for example, a vacuum cell, an electric motor, some other adjustment member or the like. The actuator can move, in particular turn, the adjustment lever 102 in the direction of an arrow 110, as a result of which the adjustment shaft 100 is turned about the rotational axis 108 in the direction of an arrow 112. This in turn rotates the adjustment wheel 98 about the rotational axis 108, which involves a rotation of the adjustment ring 66 about the rotational axis 24 in the direction of an arrow 114 via the tooth systems 104 and 106. Through this rotation of the adjustment ring 66, the tongues 58, 60, 62 and 64 are displaced in the direction of the arrow 48 as described at the beginning, as a result of which the spiral inlet cross section A_(S) and/or the nozzle cross section A_(R) is or are adjusted. This adjustment via the tooth systems 104 and 106 has the advantages that particularly high throughput spreads of the variable turbine 12 of the exhaust gas turbocharger 10 ^(VII) can be achieved. Of course the adjustment of the adjustment ring 66 in the way described in respect of FIGS. 12 and 13 can also be applied to the other exhaust gas turbochargers 10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(V) and 10 ^(VI). The adjustment of the adjustment ring 66 and, as a result, of the tongues 58, 60, 62 and 64 by means of the tooth systems 104 and 106 also allows a particularly large adjustment angle, that is to say a particularly large adjustment angle range in the circumferential direction as shown by the arrow 48. This also makes it possible to achieve a harmonic transmission over the adjustment angle range on the basis of an adjustment angle of the actuator to an adjustment angle of the adjustment wheel 66 (tongue diverter). 

What is claimed
 1. An insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) for a turbine (12) of an exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)), the turbine (12) including a housing (14) into which the insert element can be inserted, the insert element being provided with at least one spiral port (38, 40, 42, 44) which extends in the circumferential direction (48) of the insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) over at least part of the circumference thereof and by which exhaust gas flowing through the turbine (12) is directed onto a turbine wheel (20), the insert element being open in the axial direction (49) at least one end face (82, 84) thereof for accommodating the turbine wheel (20):
 2. The insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) according to claim 1, wherein the insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) has at least one further spiral port (38, 40, 42, 44) which extends in the circumferential direction (48) of the insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) over at least part of the circumference thereof and by which exhaust gas flowing through the turbine (12) is directed to the turbine wheel (20).
 3. The insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) according to claim 1, wherein the spiral port (38, 40, 42, 44) is designed to be open at least in part in the circumferential direction (48) over the circumference of the insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) .
 4. An exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)) for an internal combustion engine, having a turbine (12) with a turbine rotor (22) disposed in a housing (14) and at least one insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) , as claimed in claim 1, the insert element being accommodated in the turbine housing (14), and having least one spiral port (38, 40, 42, 44) which extends in the circumferential direction (48) of the insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) over at least part of the circumference thereof and by which the exhaust gas flowing through the turbine (12) is directed onto the turbine wheel (20), the spiral port (38, 40, 42, 44) being designed to be open at least in part in the axial direction (49) of the exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII))at least one end face (82. 84) of the insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)).
 5. The exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII))according to claim 4, wherein the exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)) comprises a bearing housing (16) for supporting the rotor (22) of the exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)), the spiral port (38, 40, 42, 44) being open at least in part in the axial direction of the exhaust gas turbocharger (10, (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)) on one end face (84) of the insert element (36, 36 ^(I), 36 ^(II), 36 ^(III), 36 ^(IV), 36 ^(V), 36 ^(VI)) pointing in the direction of the bearing housing (16).
 6. The exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII))according to claim 5, wherein at least one lid element (86) is provided, by which at least one area of the spiral port (38, 40, 42, 44), in which the latter is open, is covered.
 7. A turbine (12) for an exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)) with a turbine housing (14) having an accommodating space (18) for accommodating a turbine wheel (20), which comprises at least one spiral port (28) through which the exhaust gas flowing through the turbine (12) can flow and which extends in the circumferential direction (48) of the accommodating space (18) over at least part of the circumference thereof, the spiral port (28) having at least one inlet opening (30) enabling exhaust gas to flow into the spiral port (28), via which exhaust gas can be guided to the accommodating space (18), wherein at least one port part (37) is provided, by means of which the at least one spiral port (28) is divided into at least two spiral part ports (38, 40, 42, 44) downstream of the inlet opening (30).
 8. An exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)) including a turbine (12) according to claim 7, wherein between a housing part (16), in particular a bearing housing (16), of the exhaust gas turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)) and the port part (37), an interspace (92) delimited from the port part (37) at least in part is formed which is connected in flow terms to the at least one spiral port (28).
 9. A turbine (12) for an exhaust as turbocharger (10, 10 ^(I), 10 ^(II), 10 ^(III), 10 ^(IV), 10 ^(V), 10 ^(VI), 10 _(VII)), with a turbine housing (14) which has at least one spiral port (28, 38, 40, 42, 44) and an accommodating space (18) in which a turbine wheel (20) is accommodated such that it can rotate and can be acted upon by exhaust gas via the spiral port (28, 38, 40, 42, 44), wherein the turbine (12) comprises an actuating device (56) by means of which a spiral inlet cross section (A_(S)) and/or a nozzle cross section (A_(R)) of the at least one spiral port (28, 38, 40, 42, 44) can be adjusted to the accommodating space (18), the actuating device (56) has at least two intermeshing tooth systems (104, 106) for the purposes of adjusting the spiral inlet cross section (A_(S)) or the nozzle cross section (A_(R)R).
 10. The turbine (12) according to claim 9, wherein one of the tooth systems (104) is provided on an adjustment ring (66) of the actuating device (56) and the other tooth system (106) is connected in a rotationally fixed manner to an adjustment shaft (100) of the actuating device (56) that can be rotated about a rotational axis (108). 